Condition responsive control for clothes driers and the like



Sept. 28, 1954 v. WEBER CONDITION RESPONSIVE CONTROL FOR CLOTHES DRIERS AND THE LIKE Filed April 13, 1951 3 S heets-Sheet l INVENTOR Vzcv-oe (2120412.

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Sept. 28, 1954 v. WEBER CONDITION RESPONSIVE CONTROL FOR CLOTHES DRIERS AND THE LIKE 3 Sheets-Sheet 2 Filed April 15, 1951 INVENTOR. Vzc 7'02 CW2 see /W/ his Sept. 28, 1954 v. WEBER CONDITION RESPONSIVE CONTROL FOR CLOTHES DRIERS AND THE LIKE 3 Sheets-Sheet 3 Filed April 13, 1951 v INVENTOR Vzcrae ((655124? HTrae Ar Patented Sept. 28, 1954 NITED STATES CONDITION RESPONSIVE CONTROL FOR CLOTHES DRIERS AND THE LIKE Victor Weber, Greensburg,

Pa., assignor to Robertshaw-Fulton'Controls Company, Greensburg, Pa., a corporation of Delaware Application April 13, 1951, Serial No. 220,764

14 Claims.

This invention relates to automatic controls for appliances such as clothes dryersand more particularly to gas burning appliances of the'described type.

Patent No. 2,533,982 discloses a domestic clothes dryer having a motor driven shell or drum in which the clothes are loaded for the drying operation which results when heated airis circulated through the load by a fan or blower. The source of heat comprises a main gas burner with which is associated the usual automatic pilot control for preventing the escape of un burned fuel together with electric ignition for the pilot burner and an overtemperature shut-off deviceto prevent hazardous conditions.

The present invention seeks to improve the disclosure of the aforesaid patent by simplifying the starting operation and reducing'the number of specialized parts to provide anovel combination. Thus, an automatic pilot control of the thermal fluid type is provided and requires no manual reset operation; An electric ignition device is so arranged as to be automaticallydeenergized following the starting operation and also requires no manual eiTort in this respect. A simple solenoid valve controls the flow of fuel to at least the main burner and'is energized under control of the thermostat which also con trols the motor-driven drum. The solenoid valve may also be controlled by the overtemperature shut-01f device for further reduction in the number of parts or a separate control may be provided for this purpose.

Other objects and advantages will become apparent from the following description'taken in connection with the accompanying drawings, wherein:

Fig. 1 is a schematic view of a domestic clothes drying apparatus embodying the invention;

Fig. 2 is a similar schematic view but showing a modified form;

Fig. 3 is a side elevation partly in section of the main thermostat control device shown in Figs. 1 and 2;

Fig. 4 is a front elevation of the control device with the cover removed;

Fig. 5 is a cross-section taken on the line VV of Fig. 3, and

Fig. 6 is a top plan view of the structure shown in Fig. 3.

Referring more particularly to Fig. 1, a main burner i ii is shown for location in a clothes drying apparatus and from which heated air is circulated by a motor-driven fan or blower I2 through the usual shellor drum (not shown). The motor it which drives the blower [2 may also drive the shell or drum as is customary in the art.

The main burner it receives asupply'of fuel from a main fuel pipe 16' in which is'interposed an automatic pilot control device l8. Electrically operable means in the form of'an electro-magnetic or solenoid valve 20 is also interposed in the main fuel pipe l6 forcontrolling the supply of fuel to the automatic pilot control device E8. The usual manually operatedcock 22 is provided for controlling the supply of fuel in themain fuel pipe [6 to the solenoidvalve 20.

Automatic pilot control device The control device l8 comprises a casing 24 having aninlet 26lfor. one end of the main fuel pipe I 6 andranoutlet 28for the oppositeend thereof. A mainvalve seat 30 isformed in the casing and has an opening Sloommunicating with the outlet 28. A -valve member 34 is cooperable with thevalve'seat 30for controlling thepassage of fuel between the inlet 26 and the valve opening 32 and isbiased by a coil spring ifirinto engagement with the valve seat 3|].

A 'valve stem 38projects from the valve member 34 through the casing 24-and into a cover member 40 for the casing 24; Supported in the cover member 40- is an actuating element ii. of a liquid typethermostat having the usual capillary tubing 44 and bulb element flfiassociated therewith. The bul b elementfeis located to be heated by the flame of a pilot burner :38 which is located inlighting proximity of the main burner lflz The pilotburner receives a supply of'fuel by way of a conduit 59 which is connec ed to the main fuel pipe lfi preferably between the gas-cock 22- and the'solenoid valve 20. The bulb element46 isadapted to contain a quantity of thermal liquid, such as-mercury', which becomes completely vaporized by the heat of the flame from'the pilot burner itand causes expansion of the actuating element 42 under such conditions. The power so generated is adapted to be transmitted to the valve stem 38 for operating the valve member 34-- to open position againstthebias of the spring 3%.

Interposed between the actuating element 42 and the valve stem 38 is a lever member 52which is pivotally mounted'in a bracket 54 carried by the cover member 40 adjacent'the actuating element 42; The opposite end of the lever member 52 supportsa plunger 56 which is slidably mounted in the casing 24 and'projects into aswitch housing 58 formed therein. The plunger 56 operatively engages-a movable contact bar 66 located in the switch housing 58 and which is biased by a coil spring 62 into engagement with a pair of relatively fixed contacts 64, 66, The contacts 64, fifi aresupported in the switch housing 53 by insulating plates 68, 10' respectively and may have suitable terminals (not shown) associated therewith.

Astandby pilot valve member 12 is positioned in the casing 24 "between the main valve member i and the switch housing 58 and is mounted on a valve stem It for reciprocable movement in the casing 24 Such movement is effected by engagement between the valve stem It and the lever member 52 intermediate the ends of the lever member 52. The valve member "52 is biased by a coil spring is into engagement with a valve seat it formed in the casing 25 and having an opening 88 therein. A standby fuel conduit 82 communicates at one end with the opening it and at the opposite end adjacent the main burner I6. A supply conduit 8 communicates at one end with the casing 24 for supplying fuel to the conduit 82 when the standby pilot valve member if is disengaged from its seat id. The opposite end of the supply conduit E i communicates with the main fuel pipe is preferably ahead of the gas cook: 22.

Main thermostatic control Referring now more particularly to Figs. 3, i and 5, a main thermostatic control device 85 comprises a housing 88 having a front cover 85% secured thereto and an open end Within which a block of insulating material is mounted. The cover 88 carries a centrally located nut 92 within which a threaded stud Q5 of an operating handle 96 is mounted. The opposite end of the stud 94 is secured to an actuating element 98 of a liquid type thermostat having a capillary tube IE0 and bulb I542 associated therewith. In this instance, the bulb IE2 is located to respond to temperature conditions caused by operation of the main burner I 3 and is not exposed to any flame. Consequently, the liquid fill may be of a nature to retain its liquidity throughout the operating range of the thermostatic device and may completely fill the bulb I62, capillary element I68 and actuating element 96 as is customary in such devices.

A button ltd carried by the actuating element as abuts a main actuating lever I55 which is provided at one end with a knife edge I88 seated in a pair of knife edged bearings i It formed on a bracket I I2 secured to the inner wall of the frame SE. The opposite end of the main actuating lever Hit is recessed at the center portion to provide a seat for one end of a tension spring I I l, the other end of which is hooked in an apertured crossbar lit of an H-shaped control lever H8.

The two legs of the H-shaped control lever H8 are provided at one end with knife edges (:0- operating with spaced knife edged bearings I formed in a channel-shaped support I22 extending substantially parallel with the base of the housing 25. An adjusting screw through the bottom wall of the housing 86 into engagement with the support I22 to adjust it on a pivotal mounting I26 located on the rear Wall of the housing 36.

A pair of arms I23, I23 of insulating material are carried by the legs of the H-shaped control lever its opposite the knife edge bearings I28. The arm I28 is provided with a contact bridge I38. The contact bridge I cooperates with relatively fixed contacts 35 mounted on the insulating block so and projecting exteriorly of the frame 8%. In this embodiment, the contact we is provided with a terminal connection I38, while the contact E35 is adapted for permanent connection with a conductor E li It will be apparent, however, that such arrangement can be modified as dictated by the circuit arrangement with which the control apparatus is used.

The structure so far described constitutes a snap-action mechanism by means of which the IM extends control lever H8 can effect contact operation. Thus, as the liquid in the bulb I92 and the capillary tube Iilil expands in response to temperatures prevailing at the point where the bulb 552 is located, the actuating element 58 will also ex" pand and urge the free end of the main actuating lever we toward the knife edged bearing we of the control lever H8. Due to the tension of the spring IN, the control lever H8 and its arms 528, :29 will be moved to the left, as vi wed in Fig. 3, with a snap-action as the actuating lever I65 moves over-center past a line between the respective bearings of the two levers. Such snap-- action causes engagement of the contact bridge ass and the contacts I36, I35 as will be apparent. In this embodiment, the contacts I3 3, I35 together with the contact bridge I39 constitute an auxiliary switching mechanism for the motor id as will hereinafter be apparent.

The closed position of the contacts I34, I35 will continue until the actuating element 33 starts to contract upon cooling of the bulb I32 whereupon a similar over-center snap-action will occur, but in the opposite direction to cause contact disengagement as the contact control lever l resumes its normal position as shown in Fig. 3. Separation of the levers I66 and H8 is prevented by a limit stop member I3I which is secured to the insulating block 98 and extends into the path of movement of the contact arm I29.

A pair of additional contacts It's, 239 are provided and are located to one side of the contacts I341, I35 as viewed in Figs. 4 and 5. These contacts It'i, I39 are supported on an insulating plate I l! which is secured to the block at and extends into the housing 86. The contact I-il is adapted for permanent connection with a conductor I 'il while the contact I35 has a terminal connection M3.

The contacts I33, I35 which cooperate with contact bridge I38 to form the auxiliary motor switch as described are also provided with bacl: contacts I i i, I 36 respectively in substantially the same plane as the contacts I31, I39. The ca-2i:

' contacts [M5, M5 form the main switching mesh-- anism for the motor I 4. These back contacts I hit and the contacts I31, I39 cooperate with a pair of contact bridges I la, I55 respectively.

The contact bridges I48, I56 are mounted upon.

separate insulating contact arms I52 carried by flexible arms I56 mounted upon the opposite bifurcated ends of a secondary lever A bracket I58 extends from the rear wall of the frame 86 and provides a pivotal mounting I for the secondary lever I56. A compression spring I62 is mounted between the secondary lever and the inner wall of the frame 88 on the side of the pivotal mounting opposite the contact bridges Hi8, use thus serving to bias these contact bridges into and out of engagement with the contacts I 54, I and I37, I39 respectively.

The secondary lever I56 is adapted to be operated during the snap-action movement of the main actuating lever I06. Thus, interengaging means on the main actuating lever Hi5 and the secondary lever IE8 are provided and takes the form of a rocker Hit pivotally mounted on the bracket I58 and having a ramp Hill formed thereon for engagement by a projection I68 formed on the main actuating lever I 56.

In order to maintain the contact bridges Edd, 550 in engagement with their respective contacts, the bias of the spring IE2 is overcome by a latching arrangement now to be described. The u derside of the rocker I64 adjacent the lever I is provided with a notch portion I for engagee ment with the wall of a slot "2"f01li'l6d' in the lever I55. A manually operableplunger I'Mex tends through the cover 83" into the housing 33 for operative engagement with the lever I56:for overcoming the biasof the coil spring I62. When the lever lee is thus'tilted on its pivotal mounting ltd, the rocker I6 1" is rotated in a counterciockwise direction by a coil spring I'It for-en gaging the notch are with the wall of the slot Hi2 as described. The plunger I'M is biased outwardly of the cover member 88 by a coil spring tit and will return to such position upon release of manual pressure upon an enlarged end'or button ice of the plunger ll i.

Secured to the exterior rear wall of thehousing 66 is a housing I82 of insulating material. The housing I82 carries on one side thereof a pair of relatively fixed contacts ISQ, IB S: with which a movable contact bridge ltd-is adapted to cooperate. Contact IE4 is adapted for permanent connection with a conductor I85 while the contact I 83 carries a terminal connection I8'I."

The contact bridge I 88 is carried by a switch arn iild of insulating material which is pivotally mounted at I92 on a bracket I3 carried by the housing E82. between the bracket IM and the switch arm I96, serves to bias the latter and the contact bridge tat into engagement with the contacts Ifit, I53.

carrying contacts 2%, 2638 respectively of their free ends. The switch arms 289', 2 2 are secured at the opposite ends to the housing :82 by screws 2% and are provided with separate terminal connections 2 iii, 2! I. The contacts 29 are adapted to cooperate with contacts M2; Rid respectively which are secured to the housing by screws 2I5.

The flexible switch arms 2%, M32 are adapted for conjoint operation to disengage from the contacts 2E2, 2M. To this end, a projectiontiii extends from the base of the housing I82 intermediate the switch arms Zilll, 292 and serves as a pivot point for one end of an actuating plate Eli? of insulating material which underlies the switch arms 2%, 2532. The opposite end of the pivot plate 1H8 is engaged by an operating bar 225 which extends completely through the housings E22 and and the front cover 88 for slidable movement relatively thereto. Such movement is effected by engagement of the projecting end of the pin 22!) by a cam portion 222 lormed on the underside of the dial 96. The cam element 222 is so oriented with respect to the dial Q5 that the desired engagement with operating bar 226 will occur when the dial is in the Off position. Cross-reference ismade with respect to this thermostatic control device tie to copending application of Weber and Kunzler, Serial No. 67,532 filed December 27, 1948 now Patent No. 2,564,868.

A coil spring I9t, operative 6. Electric ignition" An electric igniter 224' is shown on Fig. 1 as comprising a coil of wire adaptedto be'heated to incandescence by electric current supplied through a step down transformer 228 having its primary connected to line wires LI, L2. A suitable ballast 228 is provided in the secondary sircuit to the igniter 224. The connections will be described in connection with the operation of the apparatus hereinafter.

In this embodiment, an overtemperature cutout 235.? of the thermally sensitive'electric current is provided for openingthe circuit to the solenoid valve Zllupon occurrence of hazardous conditions such as failure of the main thermostatic control device 85 to operatefor maintaining safe temperature conditions in the appliance. As noted in connection with the ignition device, the circuit connections for the overtemperature cut-out 236 will be described in connection with the operation of the apparatus.

In the preferred embodiment, the fuel flow in conduit 58 to the pilot burner is under control of a pilot valve 232 which is carried on the casing 85 of the main thermostatic control 85. A projection 234 on the dial 96 is adapted for operative engagement with the stem portion of the pilot valve 232 for opening this valve whenever the dial is moved from the Off position to any temperature setting. It will be apparent that this pilot valve arrangement may be dispensed with as noted in the description of the operation of the apparatus.

Operation The system is placed in operation by manual rotation of the cook 22 to open position whereupon fuel will flow in the main fuel pipe I6 as far as the solenoid valve 20; It may be assumed that the dial 96 is in the Off position so that the cam element 222 has forced the operating bar 220 inwardly to engage the actuating plate 2 I8 and thus operate the flexible switch arms 2%, 202 to disengage the contacts 2%, 2% from the contacts 2I2, 2M respectively. Since line wires LI, L2 are connected to the terminals 2 i Ii, 2 I i the circuit is broken on both sides of the line and movement of the dial 96 in a counterclockwise direction is required to disengage the operating bar 220 from the cam element 222.

Rotation of the dial 96 from the Off position to a preselected temperature setting will serve to cause longitudinal movement of the stud it to the left as viewed in Fig. 3. This also causes movement of the actuating element 98 and the button IM to the left, but is insufficient to operate the main actuating lever I ilfiand cause snapaction of the control lever I I8. Thus, the contact bridge I30 remains in position where the contacts I34, I35'are disengaged. However, the cam element 222 has moved out of engagement with theoperating bar 22$ so that the latter no longer causes disengagement of the contacts 25%, 2% from contacts 2I2, 2l i respectively.

The button I isthen operated to cause the plunger I'I' i to engage'and move the lower end of the secondary lever I55 "on its pivot I 6i! thus overcoming the bias of the spring I62-and permitting the spring ilfi'to tilt'the rocker ISB'and engage the'notch IIil "with the wall of the slot H2. The secondary lever I56is thuslatched in itsforward position with the contactbridges-I it, I56 in engagement with the contacts I, I liiand "E31," its respectively. Due to the forward movement of the secondarylever I56 the'contact bridge I88 is simultaneously moved by the contact arm I90 under bias the spring I96 into engagement with the contacts I84, I86 as previously explained.

A circuit is now made from the line wire LI, terminal 2 It, conductor I35, contact I5 5, contact bridge I88, contact I86, terminal I81, wire 23S, contact 65, contact bar 68, contact 54, wire 238, primary of transformer 226, wire 2%, overtemperature cut-out 230, wire Z IZ, terminal M3, contact I33, contact bridge I50, contact I31, conductor MI, and terminal 2I I to line wire L2.

Since the transformer 226 is now energized, a circuit for the igniter 224 is now established which may be traced from one terminal of the secondary of the transformer 22%, wire E ie, one ter minal of ballast 228, wire 2%, igniter 22d, wire 2 38, opposite terminal of ballast 228 and wire 256 to the other terminal of the secondary of transformer 226. The dial 925 having been rotated to a selected temperature setting, the projection 23 thereon has operated the pilot valve 23?. and the fuel flowing from the pilot burner 38 is. ignited by the igniter 22d.

Simultaneously with the establishment of the igniter circuit, the solenoid valve 2i} becomes energized through a parallel circuit which may be traced by wire 252 connected at one end to wire 250 and at the opposite end to one terminal of the solenoid valve 2E3 and by wire 25 which is connected at one end to wire 236 and at the opposite end to the other terminal of the solenoid valve 26. Consequently, fuel now flows in the main fuel pipe It to the automatic pilot control device I8 where it enters through the inlet 26. When the bulb it of the liquid type thermostat becomes suificiently heated by the flame from the pilot burner 38, the actuating element 52 operates the valve stem 38 and causes the valve member M to move to open position against the bias of the coil spring 35. Fuel thus flows from the inlet 26 through the opening 32 to the outlet 28 of the automatic pilot control device I8 Where it is ignited by the flame from the pilot burner 48.

The actuating element 52 in its expanded condition serves to rotate the lever 52 of the automatic pilot control device I8 counterclockwise in Fig. 1 and the stand-by pilot valve memeber 12 is thereby moved to open position. Fuel thus flows from the conduit 84 through the conduit 82 having its open end adjacent the main burner III and is ignited thereby. The stand-by pilot will continue to produce a flame as long as the stand-by pilot valve 12 is in open position. The counterclockwise movement of the lever 52 also serves to operate the plunger 56 to disengage the contact bar 60 from the contacts 64, 65 in the switch housing 58. Such operation opens the circuit of the primary of the transformer 22S and causes deenergization of the igniter 22s as soon as the pilot burner 63 has heated the bulb J5 sufficiently to expand the actuating element 52.

At the same time, a circuit for the motor HI is established and may be traced by way of line wire LI, terminal 2H1, wire 256, motor I l, wire 258, terminal I38, contact Hid, contact bridge Hi3, contact I46, conductor I46 and terminal ZII to line wire L2. Thus, by operation of the main motor switch the motor-driven drum and fan I2 commence operation as soon as the dial 96 and push button I80 are manipulated as previously described.

When the temperature in the drying appliance reaches that which has been preselected on the dial then the control will operate thermostatically. That is, the bulb IIJZ is exposed to the heat of the main burner III and will respond thereto sufiiciently to expand the actuating element 98 and cause overcenter snap-action of the control lever I I8. The auxiliary motor switch comprising contacts I34, I35 and contact bridge I30 is thereby operated to closed position so that the circuit of the motor I4 previously traced. is not broken. During such operation of the lever IE5 the projection I68 of the main actuating lever I06 tilts the rocker I64 and disengages the notch I10 from the wall of the slot I12. The secondary lever IE6 is thus disengaged and the contact bridges I48, I50 carried by this lever are thereby disengaged from their related contacts simultaneously with disengagement of the contact bridge I88 from its related contacts I84, E86 by operation of the pin I98.

Thus, the opening of the contacts I38, I32, causes deenergization of the solenoid valve 29 through the opening of the described circuit and fuel to the main burner Iii is cut-off. The main motor switch comprising contacts M5, M6 and contact bar I48 is also opened but the auxiliary switching means comprising contacts It'd, I35 and contact bridge I30 serve to continue the circuit to the motor M as described and after the solenoid valve 20 moves to closed position in order to provide a cooling down period before the ap-- pliance becomes fully shut down. It is apparent that the control device can be adjusted so that upon a rise in temperature at the bulb H52, the auxiliary switch means for the motor I I serve to close the contacts I34, I35 thereof just below the preselected setting. However, as long as engagement between the contacts I34, I35 and contact bridge I30 occurs substantially simultaneously with the disengagement of the other contacts due to the desired snap-action or the control lever I is then the operation of the motor I I will not be interrupted. When the temperature at the bulb I92 drops an amount corresponding to the diiferential of the thermostat, then the actuating element 83 contracts sufficiently to cause overcenter snap-action in the opposite direction. The auxiliary switching means is therefore opened and since the contacts I34, I35 are disengaged from the contact bar It then the motor It will cease to run.

In the described embodiment it is unnecessary to rotate the gas cook 22 to closed position in order to shut-01f the fuel flow to the pilot burner 68. It is apparent that rotation of the dial st to Off position will serve to disengage the projection 234 thereon from the pilot valve and fuel flow in the conduit 5% will cease.

In the event that the flame at the pilot burner 48 becomes extinguished during normal running conditions, then the bulb 46 will become cooled and the actuating element Q2 of the automatic pilot device I3 will contract. Consequently, the lever member 52 will be rotated in a clockwise direction under bias of the pilot valve spring 35 causing the pilot valve 34 to move to closed position relative to its seat 30. Flow of fuel to the main burner I0 is thus cut-off by operation of the automatic pilot device I8. t will be apparent, however, that fuel will continue to flow in the pilot conduit 5!! to the pilot burner 4'8 automatic reignition will occur if the main thermostatic control 85 is still in the original operating condition with the dial 9% in an On position and the push button I35 set in its inward position.

If during normal operation of-the appliance, the dial 35 is turned from the On to the Oif position then the main thermostatic control device 85 will operate to open the circuits-for both the motor Id and the solenoid valve 20. However, the pilot burner #38 will also become extinguished by such operation since the pilot valve 232 would no longer be held open. The appliance can be reloaded under such conditions and the system does not have to complete its full cycle.

It may occur that the dial-96 is rotated from On to Off position when thebulb 45 f the automatic pilot I8 is heated'and then immediately to On position. Thisrapid recycling operation would first turn oif thefuel to the main burner as and the pilot burner-58 and thereafter turn it on again withoutenergizationof the igniter. The automatic pilot control I53 would be unable to operate since the actuating element as would be expanded and maintaining'the main valve member 3 open. However, since the standby pilot valve member 12- is alsolbeing mainopen, this burner would continue toproduce a flame for igniting the main burner It! and preventing escape of unburned fuel.

Should the temperature in the appliance exceed a predetermined safe limit as may happen in case of a defective thermostatic control device then the overtemperaturecut-out 236 would operate to open the circuit of the solenoid valve shut-on the supply of fuel to the main b ner The motor I i would continue to run under such conditions.

Fig. 2 embodiment The modified form shown in Fig. 2. is substantially the same as that previously described and sim ar reference numerals have been usedfor corresponding parts. The only essential difference is that the overtemperature control23il in Fig. l is replaced by a liquid type overtem erature control 259 which serves to operate a valve device 26?. interposed between the solenoid valve 2!} and the automatic pilot control 523. As will be apparent, whenever the temperature at the bulb 2S6 exceeds safe limits the valve will be operated to shut-off the fuelin the i 11 fuel pipe 5 and thus discontinue operation of the main burner [8.

Various changes may be made in the details. of construction and arrangement of parts without ng from the scope of the invention as .defined in the appended claims.

7 claim: A control apparatus for fuel burning applithe main burnenswitching means operably energization of said igniter, electrically 2 means for controlling the fuel supply main burner and adapted when-enerpermit such supply, second switching "ble for controlling the energization of d 'rically operable means andtheheat dis .libuting means, third switching means operfor controlling the energization oftheheat 3 tributing means independently of said second tching means, means responsive to a,preidetermined temperature condition caused doy the main burner for operating said second and third switching means to cause deenergization of said gize;

ing deenergization of the heat electrically operable means while the heat distributing means remains energized, and means operably associated with said third switching means for causing deenergization of the heat distributing means upon a variation in said predetermined temperature.

2. A control apparatus for fuel burning appliances having main and pilot burners and electrically operated heat distributing means, comprising in combination, an electric igniter for the pilot burner, control means responsive to a flame at the pilot burner and including a movable element for controlling the fuel supply to the main burner, switching means for controlling the energization of said igniter, connecting means between said movable element and said switching means for deenergizing said igniter after said flame has been burning for a predetermined period, electrically operable means for controlling the fuel supply to the main burner and adapted when energized to permit said supply, second switching means operable for controlling the energization of said electrically operable means and the heat distributing means, third switching means operable for controlling the energization of the heat distributing means independently of said second switching means, means responsive to a predetermined temperature condition caused by the main burner for operating said second and third switching means to cause deenergization of said electrically operable means while the heat distributing means remains energized, and means operably associated with said third switching means for causdistributing meansupon a variation in said predetermined temperature.

3. A control apparatus for fuel burning appliances having main and pilot burners and electrically operated heat distributing means, comprising in combination, an electric igniter for the pilot burner, control means responsive to a flame at the pilot burner and including a movable element for controlling the fuel supply to the main burner, switching means biased to a closed position for controlling an energizing circuit for said igniter, connecting means between said movable element and said switching means for opening said circuit after said flame has been burning for a predetermined period, movable means biased to a closed position for controlling the fuel supply tothe main burner, electromagnetic means for operating said movable means to an open position, a circuit for energizing said electromagnetic means and the heat distributing means, second switching means having open and closed positions for controlling said energizing circuit, manually operable means for closing said second switching means to establish said energizing circuit, third switching means having open and closed positions for controlling part of said energizing circuit independently of said second switching means, means responsive to a predetermined temperature condition caused by the main burner for opening said second switching means and substantially simultaneously closing said third switching means for deenergizing said electromagnetic means while the heat distributing means remains energized, and means operably associated with said third switching means for causing deenergization of the heat distributing means upon a variation in said predetermined temperature,

4. A control apparatus as claimed in claim 3 wherein a pilot valve member is provided for ll controlling the fuel supply to the pilot burner, and means operably associated with said manually operable means for operating said pilot valve member during said controlling operations.

5. A control apparatus as claimed in claim 4 including means responsive to an abnormal condition caused by the main burner for terminating the fuel supply thereto.

6. A control apparatus as claimed in claim 5 wherein said condition responsive means includes a thermal out-out in circuit with said electromagnetic means and exposed to the heat of the main burner for deenergizing said electromagnetic means under said abnormal condition.

7. A control apparatus as claimed in claim 5 including a standby pilot valve member, said connecting means extending between said movable element and said standby pilot valve member for operating the latter to open position upon expiration of said predetermined period.

8. A control apparatus for fuel burning appliances having main and pilot burners and electrically operated heat distributing means, comprising in combination, an electric igniter for the pilot burner, control means including a main valve member movable between positions for controlling the fuel supply to the main burner, thermally responsive means located to be heated by the pilot burner and operable when heated for moving said main valve member to a fuel supply position, a standby pilot valve having a movable valve member, switching means for controlling the energization of said igniter, connecting means extending from said main valve member to said standby pilot valve member and said switching means for operating said standby pilot valve member and deenergizing said igniter after said flame has been burning for a predetermined period, electrically operable means for controlling the fuel supply to the main burner, a thermostatic control switch in circuit with said switching means and operable for controlling the energization of said electrically operable means and the heat distributing means in accordance with temperatur conditions caused by the main burner, manually operable means for adjusting said control switch for said controlling operations, and means for connecting said standby pilot valve to receive a fuel supply irrespective of the deenergised condition of said electrically operable means.

9. A control apparatus as claimed in claim 8 wherein a pilot valve member is provided for controlling the fuel supply to the pilot burner, and means operably associated with said manually operable means for operating said pilot valve member during said controlling operations.

10. A control apparatus for fuel burning appliances having main and pilot burners and electrically operated heat distributing means, comprising in combination, an electric igniter for the pilot burner, control means responsive to a flame at the pilot burner for controlling the fuel supply to the main burner, switching means operably associated with said control means for controlling the energization of said igniter, electrically operable means for controlling the fuel supply to the main burner and adapted when energized to permit said supply, a thermostatically controlled switch operable for controlling the energization of said electrically operable means and theheat distributing means in accordance with a predetermined temperature condition caused by the main burner, a second thermostatically controlled switch operable for controlling the energization of the heat distributing means in accordance with a predetermined variation in said temperature condition, and means responsive to an abnormal condition caused by the main burner for terminating the fuel supply thereto.

11. A control apparatus as claimed in claim 10 wherein said condition responsive means includes a thermal cut-out in circuit with said electrically operable means and exposed to the heat of the main burner for deenergizing said electrically operable means under said abnormal condition.

12. A control apparatus for fuel burning appliances having main and pilot burners and electrically operated heat distributing means, comprising in combination, an electric igniter for the pilot burner, control means including a main valve member movable between positions for controlling the fuel supply to the main burner, thermally responsive means located to be heated by a flame at the pilot burner and operable when heated for moving said main valve member to a fuel supply position, a standby pilot valve hav ing a movable valve member, switching means for controlling the energization of said igniter, connecting means extending from said main valve member to said standby pilot valve member and said switching means for operating said standby pilot valve member and deenergizing said igniter after said flame has been burning for a predetermined period, electrically operable means for controlling the fuel supply to said automatic pilot means, second switching means operable for controlling the energization of said electrically operable means and the heat distributing means, third switching means operable for controlling the energization of the heat distributing means independently of said second switching means, means responsive to a predetermined temperature condition caused by the main burner for operating said second and third switching means to cause deenergization of said electrically operable means while the heat distributing means remains energized, manually operable means for adjusting said temperature responsive means for said controlling operations, and means for connecting said standby pilot valve to receive a fuel supply irrespective of the deenergized condition of said electrically operable means.

13. A control apparatus as claimed in claim 12 wherein said third switching means has means operably associated therewith for causing deenergization of the heat distributing means upon a variation in said predetermined temperature, and means responsive to an abnormal condition caused by the main burner for terminating the fuel supply thereto.

14. A control apparatus as claimed in claim 13 wherein a pilot valve member is provided for controlling the fuel supply to the pilot burner, and means operably associated with said manually operable means for operating said pilot valve member during said controlling operations.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,883,242 Bogle Oct. 18, 1932 2,168,859 Bergey Aug. 8, 1939 2,218,771 Roberts et al. Oct. 22, 1940 2,275,962 Herbster Mar. 10, 1942 2,486,315 Morris Oct. 25, 1949 2,538,952 Yates Jan. 23, 1951 

